WEST PALM BEACH, Fla. -- The parents of a Florida toddler who died of a drug overdose have been charged with neglect resulting in death.

A medical examiner determined that Darius Clark, 21 months old, had both cocaine and Oxycontin in his system, The Palm Beach Post reported. The boy died at his home in Riviera Beach in April.

Patrick Galligan, a police sergeant, said that the boy had such high drug levels the combination was "strong enough to kill an adult."

The mother, Tocarra Nobles, said that she woke up in the middle of the night and wiped some "white stuff" off her son's face. When she woke on the morning of April 21, she discovered that he was unconscious or dead.

The father, Vincent Clark, tried to revive the little boy with CPR.

Investigators say that Nobles had signed an agreement with child protective services that Clark would not be in the home. He faces unrelated felony charges including armed robbery.

Nobles' parents are supervisors with the Palm Beach County Sheriff's Office.

The dead boy's siblings are being cared for by their maternal grandmother.